Friday, March 29, 2019

Barc Scientists Interview. 

Name: -Sachin Solanki
Interview date: -July 21

There were 7 members in the panel. 
The questions started. 

To prepare for Mtech interviews in IITs click here. 

1. Have you prepared for the interview? 

I confessed, "Sorry sir, my final year exams over just yesterday and I haven't brushedup a single subject but I'm confident enough about the basics of all the electronics subjects and also my final semester subjects. 

2.What are your final year subject? 

I answered, " VLSI design. 
                         Mobile communication. 
                         TV and RADAR. 
                         Advance communication. 

They told ,"okey then ,we will Start with VLSI design. 

3.How you can make Inductor, Capacitor, Resister using VLSI design? 

4. What is input/output graph of inverter? 

5. Draw circuit diagram of inverter.  How you can make clock using arrangement ?

6. Your Biodata says you have completed training in VLSI,  just give the full form of SPICE software and explain its working. 

7.Basic property of inductor in VLSI point of view. 

Now they moved towards Mobile Communication related questions. 

8. Explain CDMA. 

9. Working of CDMA and Multiplexing. 

10. How you will show all other signals in CDMA is noise.  And which type of noise it is? 

Then given a waveform and asked basic parameters used in it. 

But I hadn't understood the question well. So I was hesitating to answer but their hints made me comfortable so I could understand their approach towards the answer. 

Now they given me one capacitor-resister circuit and asked to draw the output if input is a square wave. 

I drawn very quickly hence they asked, "are you sure".

I said  " Yes sir. "

Now they asked about asynchronous circuit. 

Difference between synchronous and asynchronous counter. 

11. Draw given waveform using asynchronous counter. 

My interview lasted for about 2 hours.  I was not satisfied with the interview. I was preparing to go to home.  Within five minutes a person came with the medical slip. 

I was second candidate among 10 people who got medical slip that day. 

It was a great experience. 


Thursday, March 14, 2019

 Mtech Admission Interviews.

   Hello everyone ,
I just don't want to disclose my name so I'm posting it anonymously. Currently I'm working in BSNL as JTO. I qualified GATE 2017 (EC) with score 720 and all India rank of 850.
   With this score and rank I applied to old IITs like IITD,IITK,IITKGP. I would like to share my experience of interview taken for the Mtech admission at these old IITs.

Sourabh Patil (IIT Bombay Mtech communication systems) Mtech admission test and interview.

  • IIT Delhi ( Communication Systems)
Questions related time shifting, frequency shifting.
Significance of causality and asked to explain sampling theorem.
Decimation and Interpolation of sampling rate. After that they had given me a question related sampling rate. I remember the question.
Q. If sampling rate of CD is 44000and the device reads at the rate of 110kbps then the rate at which we have to apply interpolation and decimation?

I answered,"5 times interpolation followed by 2 times decimation."

Some questions related to modulation techniques like frequency and phase modulation using capacitor. Explain differentiation block.

Difference in equations and block diagrams of frequency and phase modulation.

Then they asked personal questions regarding family background and all.
Interview lasted for about 20 minutes.
I was selected.

  • IIT Kanpur (VLSI)

Questions related to transistors i.e. significance and use of transistors.

Q.How can we affect output resistance without internal changes?

My answer was , by applying external to Vcc or ground either at collector or emitter junction respectively.
Same question for input resistance also.

Now they asked questions on my Btech project.
After that asked ," Which is your favourite topic in mathematics? "
I said probability. Then they asked to explain conditional probability. A question was given to solve which was exactly similar to one of previous year GATE conitional probability question.
Then a question on double integration and GREENs theorem.
 I got selected here too.

Also I got direct admission in IITKGP.
For Mtech+Phd program.

In my opinion the main reason I got these many calls from IITs was in year 2017 so many vacancies in PSUs. Only BSNL had 2000 vacancies hence most of the candidates headed towards PSUs.

My suggestion to you guys just read and revise till the last day. For further queries you can mail me.


Wednesday, March 6, 2019

   IITB Mtech Admission Experience

For councelling Guidance and College preference guidance click here.

   I am Sourabh Patil.Currently doing my M.Tech in Communication Engineering (RA) from IIT Bombay. My GATE score was 692 in GATE2018 and my all India rank was 575. I was pretty sure that I will get a call for positio of RA from IIT Bomaby on the basis of previous years scores vs marks data.
There are mainly two ways to get admission for M.Tech in IIT Bombay. Those who have ranks in top 100 or so (probably) get direct admission as TA(Teaching Assistant) which is a 2 years M Tech course. And other one is called RA(Research Assistant) which is a 3 years M Tech course, for this you get call until 2000 or so rank as per my information.
The main fact that everyone should know that in the end both RA and TA has same demand in the so called job market, I would rather say RA ones has more time to gather knowledge than TA.
Once you get call for the position for RA you have to keep in mind you are gonna go under lots of filters so that they can get the right candidates. First of all when you get accomodation and all you get nice introduction from HOD of Electrical Department Prof B G Fernandes ( atleast at my time he conducted that ). He told us about the RA position what they are required to do and so on. At IIT Bombay in Electrical Department there are 5 specializations viz Communication, Electonic System Design, Microelectronics, Control and Computing, Power Electronics.
Under RA position there are two catagories one is IRA ( Institute RA ) other is PRA ( Project RA ). IRA s are responsible for the managing and conducting the labs in EE dept and PRAs are responsible for the working and managing the labs of certain predefined professors. So basically PRAs have to work under the professors for all the 3 years starting from 1st year.
   After giving all the briefing about the positions of RA s we were told that we have to write one exam which is mixed of all the subjects. This exam dont have any predefined structure. It has MCQs, descriptive questions, True or False,etc. But dont think that this exam will be too hard and so. Basically what they check is in which way you tackle the question. So you should be knowing basics quite well and should be able to present it in the answer sheet. Even if you dont get the end answer correct its fine they do consider parital marking.
After this exam ( Day 1) they display the result in the same night itself. From that they select around 200 or so candidates of 3 types. First which are called for IRA, second for PRA and third for both. They decide this by giving some weightage to the test and some to your written exam but mostly major part is dependent on the written. And on that, the questions that you have tackled in the paper they set cutoffs for IRA, PRA and both. The ones with highest score get call for both. For IRA and PRA  they see their requirement what they need. For example they gave some programming and networking questions in the exam so who scored well in those and fair marks in other sections gor call for IRA only as they need some IRA s in PC lab of EE dept.
Story doesnt end here. There are more tests you have to pass. As at the end of the day 1 you know for which  you have been called for. I was called for both IRA and PRA. And while filling the form I did give preference for IRA as they have more mobility in the curriculum.
Click here to Continue...


  IIT Bombay Mtech Admission Experience.

For councelling and college preference guidance click here.

   on Day 2, those who are selected for PRA, have to appear for the interview which is taken by IITB profs. For that we were given the projects that were running currently in EE Dept under different profs. So we requied to give 5 preferences according to our interest which is hard thing to do at that time, atleast for me as  I was not much aware in which project what kind of work we are gonna do. They do gave us abstacts of the project which we can read and give preferences accordingly.
   This process should be done by PRA and both selected candidates. This interviewing process takes place from 8 AM till 10-11 PM, as candidate undergo atleast 3 interviews. I will brief what do they ask after I go through all the selection procedure.
Now we will see what happend with IRA and both selected candidates. As my preference was for IRA I was more concerned about this one. For IRA they have tests according to different labs that they have in EE Dept. I remember on test was for Wadhwani Electronics Lab (WEL), Micro Lab and other was for PC lab of EE Dept and CC (Computer Center) IITB. So basically there is one test for your experience with electonics stuff, opamp, function generator, DSO, etc. Other test is to check your programming skills. My personal inclination was towards electronics stuff so I appeared for this test only.
Now I will brief about what kind of questions can you expect in the written test. Written test is mostly dependent on your GATE syllabus only. I would suggest that after GATE dont stop studying your subjects till you get admission in any good college. Do brush up your basics. Descriptive qustions seems hard to do but they are very basic, at my time they did ask how would you get a ramp function using opamp. For this they said you can assume some basic thing like that. So dont worry about the end answers just read the question well see what is expected and try to answer it in your language, just be sure that your answer is clear. For the PRA interview they asked me why did you choose this project as your first preference.
   This is very important that you should choose your preferences right. I told them as my Major project in B.Tech was agricultural related as this project is I have some knowledge about some things in this project .Then they asked about my project in more in depth. I answerd them as I could. They asked me whether I did all those thing in my project on my own or not, as they require the candidate to have some basic knowledge in that field. Actully in such interviw you have to drive them to your field of interest in any way possible. One of my friend was asked to derive some EMT s formula. So it merely depend on you how do you answer and in some cases your luck also. But do not lie infront of them remeber that they are one of the finest professors in our country who has seen thousands of students like us. If you dont know something they accept it and tell them the same.
   They do help you to get to the answer as they also know sometimes under pressure we forget many things so confidence and honesty is the key for PRA interview. Now lets jump to IRA test. I appeared for WEL test. This was 3 hour long test. They gave us all the components that are sufficient for the experiements. All the datasheets of the Ics and all. There was one problem having 3 subproblems. We were asked to perform some kind of experiment using DAC, some amplifiers and up counter I guess. In first question we were asked to draw the outpur that we are getting on DSO. Second question was that if it was same as expected output or not. And third was if there is some error in output then what that can be and how it is resolved.
    These all outputs you have to show to the TA or RA that are present beside the table and write your comments in the answer sheet. So many students are out of touch from the breadboard and other devices so they fail to get the output. I was out of touch too due to GATE prepartion and all but I got the answers as I used  to work in techincal event team in my B.Tech college. So folks its totally on yours skill set how you perform in this test. Some did well in programming test, as I was not good in that part I appeard for this one only.
 So in the end you will get mail if you are selected in one or two weeks. As I gave IRA as my preference I got selcted as IRA in WEL lab. Doing M.Tech in one of the best institue in India thoroughly changes you as a True Engineer. So do stive for the remaining days. Put your 100% and start from now. I hope that I gave some helpful inputs.All the best!!!!
Feel free to drop me mail for any queries


Friday, March 1, 2019

  Councelling Guidance.

©Sourabh Patil (Mtech IITB Communication Systems)

   It is very important to analyze which institute is best according to our GATE score and all India Rank. Otherwise it's waste of time and money.
   Key fields in which most candidates prefer to do Mtech are

For BARC exam preparation strategy, previous year question paper and personal interviews click here.

  • VLSI and Microelectronics.
  • Communication Systems.
  • Signal Processing.
  • Electronic system.
  • Control and computing.
  • RF and Microwave.
  • Photonic.
Preference to the institute and related fields is very very important. VLSI is having greater placements than other branches.
   Here's the table which can guide you about Rank or Score versus Institute and field.
       AIR/SCORE                  INSTITUTE/FIELD

  •  1 to 10                             any IIT/IISC VLSI
  •  25 to 30                           IITB VLSI
  •         <50                            IITM VLSI
  • Score>800                        interview call from                                             IITK or IITD (VLSI)
  • Score >950                        direct admission to                                             VLSI in IITD
  • AIR 300-500                     VLSI in top NITs
Top NITs ranking

  1. Tirchy
  2. Surathkal
  3. Warangal
  4. Calicat
This is for general category candidates.For OBC multiply it by 3.

Top rankings for IITs for VLSI.

  1. IISC
  2. IITB
  3. IITM
  4. IITD
  5. IITK
  6. NITT
  7. NITK
  9. IITG
  10. IITR
  11. NITW 
  12. NITC
Up to 750 rank you can get interview call letter from Texas instruments sponsored ms program in IITM.
Along with top IITs IITH, IITBBS, IITGN,IIT indore are also considerable.

Candidates having ranking between 2000 to 4000 can apply for BITS ,DTU,VTU .
 In IITB rank below 700 can get interview call for three years Mtech program.
Next comes communication systems engineering. All IITs and IISC have this stream.
AIR within 900 can put you in some top NITs for communication systems. If your rank is greater than 2500 then there are chances in spot rounds or go for the good Government colleges.
For PH till 10000 ranks also can get top IITs And NITs.

Next post will be Sourabh patil's marks rank and overall procedure(test/interview)
So, be updated.


Monday, February 11, 2019


For ISRO Scientist interview click here.

Previous year question papers play an important role in any type of competitive exam preparation.
Here is the BARC 2016 question paper.
Click on the image you can see larger image.

  Analyze the type of questions asked and their depth. Anywhere on the internet, you will not find BARC previous year question papers. It is a memory based question paper consists of 72 questions try to solve within one hour.


Here is my scorecard.

I missed the cutoff just by 26 marks i.e. 9 questions only. When time was up,  16 questions remained unsolved, in my opinion, it's the exam of time management. If you manage time well you are done. Try to solve the minimum 60 questions correctly out of 100 questions.


I recommend solving previous year GATE questions and ACE academy PSU books. I solved that only. some questions do repeat as it is from previous year GATE and IES exam.
I followed this youtube video for the syllabus

BARC examination tips by PARVIN CHAUDHARY AIR-1 in ISRO 2016.


I haven't prepared instrumentation part and I studied C language in degree but at this time I had not revised. So to score better than other people you should be prepared with C and instrumentation.
This will take you above the threshold.

There will be around 15 questions from instrumentation i.e. ammeter, voltmeter, wattmeter, multimeter regarding questions.
Some questions from C language so be prepared with C language basics. The questions will be like what will be the output of the given program?
BREAK and CONTINUE keywords functions in the program.

click here for BARC interview experiences of candidates who attended it.

Any further queries relevant to the exam you can comment or mail me.

Good Luck.


Monday, January 28, 2019


B-Tech -ECE.
Applied for DGFS-09.
Got Medical slip.

Interview Date: 2 July 2009


This is Raghavan.
Interview panel consists of 5 people but one of them was checking my certificates only. Remaining four interacted more. Just before attending the interview I got admission in IIT-KGP. But it was not there in sponsored courses it was my first question. 

1) IIT or BARC?

I said BARC.

  When the interviewer asks you such type of questions then a youtube video
          A Talk With Shubham Dabir
will help you to tackle them. In this he has given 4-5 PSU interview experiences as he is GATE 2017 topper (AIR-75).

  Now they asked me to tell them if I knew what type of questions being asked by the panel to previous interviewees.
This was a shock for me. I said I remember one. Asked me to tell the question and solution. I told.
Then I was given a block diagram. Input is the clock. Output should be 

00 , 01 , 11, 10 .

I was asked to design that block and derive it step by step.
 Next they asked me to pen down my fav 5 subjects.

1. Networks

2. EDC

3. Digital Electronics & Microprocessor

4. Analog 

5. Control Systems.

Then they asked me questions like.

2) If we want to indicate 0 and 1 using glowing LED, how to do that?

3) how LED works?

This is one of the favorite questions of BARC scientists.


4) how do you drive the LEDs with your block.

Do you need extra cost? If so design that. How much current does a typical gate output would be?

5) some typical questions on TTL logic.

Voltage level, fan in, fan out ... And so on.
How you will get the power supply for your gate.

Then that question stretched to the topic like AC generation.
Conversion to DC.
Rectification and Regulation.
Zener diode construction and working principle.

6) Application of feedback in voltage regulators.

For all these questions I asked to draw block diagrams and asked to explain their level of satisfaction.

7)Now they came upon OP AMP.

Pin diagram of 741.
Design voltage amplifier of particular gain.
Inverting, noninverting...How will you get that gain?
How can you apply KCL directly at an opamp input terminal?
Ideal opamp circuits.
Why opamps are not ideal?

DC defects of the opamp in a voltage amplifier.

What happens if we interchange the connections to pin 2 and 3.

Draw output. Power supply voltage range. Saturation conditions. A range of resistance in the feedback path and input terminals.

8) Explain LPF ckt with an opamp.

Draw output for some typical inputs.
LPF with passive components?

9)what happens if few resistors/capacitors are added series/parallel?

And output for some typical inputs.

Finally, one irregular signal was shown. 

10) suppose this is voltage across capacitor/inductor

Derive and plot the current waveform for each.

I was asked to leave after that and asked to wait for 5 min. Later I got a medical slip, thank God. I can't describe.

They didn't ask about my project.
My interview lasted for around one hour. Throughout my interview, sometimes I could not recollect and answer some questions in a flash they made me think.
Provided me enough hints.
My panel was amicable but sometimes I felt that I'm nowhere, I'm not up to the standard they wanted. Overall it was a very good experience...!!!

  Here you can find Electrical Interview Questions.


Friday, January 18, 2019

INTERVIEW EXPERIENCE AT ISRO (Indian Space Research Organisation ), New Delhi.

Interview Date: 2nd Jan 2017.

 An interview panel was of 10 senior scientists took my interview for roughly 25–30 minutes. I am giving the entire interview process here.

For BARC exam preparation and to practice interview questions click here.

   They didn't ask me about any favorite subject or favorite topic. They just started asking various questions.


1) What was your final year project? 


2)What are 3 practical uses of your project?

I answered it properly. 
Then they told me to draw the circuit diagram of the switch relay circuit used in my project.


3)Any 5 differences between an open loop system and closed loop   system.

After my answer, they put some cross questions regarding bandwidth and stability of both the systems.


4) Types of Modulation and their principle applications.

Then they started asking about CDMA, GSM and UMTS standards.
They told me to elaborate on the differences between TDMA, FDMA, and CDMA in a practical manner.
       I answered them properly as they are the most asked interview questions for ECE students and prepared them well. From here they jumped to the definition of Lossless channel, Random channel and Deterministic channel and told me to draw each on the whiteboard.


5)Can you tell us about Huffman coding basics and significance in data compression?

As I have created a YouTube video on data compression using Huffman coding I had no problem with that.

Another panel member asked me about LEO and MEO. I answered about their application ranges but I was unaware of their heights. He also asked, “Does the mass of satellite has any impact on its velocity or not”. I answered it with confidence.
      Then another member jumped into the power electronics and started asking about Triac, IGBT, Power Mosfet, SCR, SCS and Snubber circuits. I was confident only with SCR hence answered that and said “ Sorry Sir I don't know” for the rest ones.
Due to my weak response, they shifted their gears and asked me about the diamagnetism and their use in Maglev trains which I answered perfectly.

Then they asked the differences between PD, APD and PIN diode which I answered with ease.

At the end stage of Interview panel head started telling the silent panel members “ Thoda Thoda aap bhi pucho Sir, Bahut hua theory thoda sa practical pucho isse.

Then he asked the last question of my interview


6)Can you design the automatic dusk down traffic light? 

I said yes and designed the circuit of LDR based dusk down an automatic traffic signal. After coming out of the hall I realized the blunder that I forgot to put a comparator in the circuit diagram before LDR to compare the intensity levels.

           Unfortunately its not a success story. I was one among them who's dream of joining ISRO as a scientist remained dream again.

It's hard to share the failure story but I think my experience, statics, and my
mistakes could help others in their preparations.


⏩ISRO( Indian Space Research Organisation ) , Delhi.

Interview Date: 22nd Nov 2016.
Selected as Scientist SC in ISRO.

Hi, I am Navneet Kumar.

As I entered the room there were about 8-10 interviewers sitting on the other side of a U shaped table and in front of them in a chair, I was supposed to sit and answer their questions. First, the Chairman asked me for my introduction which I gave very briefly, then he asked me 3 of my favorite subjects.

I said " Digital electronics, Signal theory, Electronic devices".

Digital expert asked me the following questions-

1)What is FPGA?

I did not know much about it and just gave him its full form.

He said" explain its functionality "

I went silent and said I don't know sir.

2) Have u read about logic families?

Yes, sir!

3)which is the fastest logic family and why?

(I gave a good answer and he seemed satisfied)


4)why CMOS is used more in practical applications?

I answered it well


5)Explain Noise figure, Fan out etc etc..

I answered them 

6)Difference between DTL and DCTL?

I explained DTL but had not heard about DCTL till then! so he let me go with that.


7)Explain SRAM and DRAM?

I answered it.


8)What are PLDs and what is the Difference between PROM and PLA?

I answered it decently enough.
Then he passed on the baton to signal theory expert.


9)what is Digital signal processing?

I somehow tried very hard to explain it which was certainly not enough for him and he asked me a counter question.


10) why DSP is used?

I had not prepared anything for that so I could not answer it.
he said, "it's okay if you don't know".
Then came from out of the blue "Analog electronics expert".
I was sent to the whiteboard right behind my back.


11)Design straight line equation y=mx+C with an op-amp?

I made it and he said, "Don't you think it'll have design issues, I saw my design and gave one alternative solution to which he was fairly satisfied."
then he quick-fired me with 4-5 op-amp theory questions like Slew rate, CMRR, gain bandwidth product etc atc.. (I answered them all)

Chairman then looked into my BIO-DATA form and said, "You made a project on 8085 microprocessor?"

"Yes," I said.
He asked me to explain it?
I explain it to its entirety and he was okay with that
Then he asked me some project specific questions like:


12)why did you use RST7.5 and RST6.5?(I had used interrupts in my project) etc etc..

Then again came the Digital expert.


13)Difference between TRAP, RST5.5, RST6.5 and RST7.5?

I answered.


14)Difference between EPROM and EEPROM? Which ROM did you use in your project?

I told him the difference and also I had used EPROM and told him why I used it.
As I was near to the board so he thought of utilizing it again.


15)Draw a timing waveform through a D flip flop and indicate set-up time, hold time and propagation delay in it?

I drew it and he made sure I make it very neat so that he could clearly see every delay in detail and gave instructions throughout in the process.

16)Master-slave FF working, Direct bandgap semiconductor etc..

Then I came back to the chair and chairman said "OK! you can go now"
"Thank you", I said.

I was giving interview unhurriedly and was keeping calm in answering every question. Also, I gave all my answers in English so I think it's better to answer them in English as most of them are comfortable that way.
Being spontaneous is very important as they don't give much time to think.

I scored 129/240 in written (51 attempted 45 correct 6 incorrect) and got 74.40/100 in the interview and was at panel position 66/201 after the interview.


Wednesday, January 2, 2019

⏩BARC (Bhabha Atomic Research Center)

Interview Date:26th June 2009.

OCES Interview.

Observe the level of BARC interview questions. Let's hear in the words of the candidate.

"I was the first candidate that day, first of all, I wished good morning to the panel. On return the main person wished me. Then he asked me where I was studying and how waw the accommodation facilities. Actually, they were trying to make me relax.

Then he asked me "tell your 5 fav subjects... I told

1. Linear Integrated ckt.
2.Control system.
3. Signal and system.
4. Digital Electronics.

Interrupted in between they didn't allow me to tell 5th subject and started questioning.


1)Draw inverting amplifier of gain 100.
2)Draw noninverting amplifier of gain 100.
3)Draw differential amplifier of gain 100.
4) Suppose CMRR of the above differential amplifier is 100db then find common mode gain.
5)Find the exact output of the differential amplifier.
6)Common mode voltage of the differential amplifier.
7) Consider a 10v dc connected in between inverting and noninverting terminal. And 2.5v dc connected between noninverting and ground. Now asked to calculate output vtg, common mode vtg, and difference mode vtg.
8) What is the input impedance of the inverting amplifier.....
And continued...


1) Draw an arrangement to indicate the selected pin index and the output state of MUX.
2) Generate a clock signal for a watch(i.e. of 1Hz).
3) Generate a 120v 60 Hz clock signal.
It can be generated d using high tension transformer and related ckt .but didn't know.
4) How a stable clock can be generated.
Ans is using crystal oscillator.
5) The frequency of oscillation of crystal oscillator.

6) What is the practical significance of Q factor?
7) Draw graph of Q factor of series R-L-C ckt.
8) What is really mean by an increase in and decrease in Q factor in ckt?

Signals And System.

1) we have got three identical bandlimited signals with us ...we are required to send them one after other allowing a specific delay between each of them. Also, we have to code these signals before transmitting.
2) What all ckts should be used before an ADC.
and so on up to 1:45hours...." I was interviewed.